The present invention relates to a motor-driven compressor including a drive circuit, a control circuit, and a communication lead connected to the control circuit.
For example, Japanese Laid-Open Patent Publication No. 2010-112261 discloses a motor-driven compressor that includes a compression portion for compressing refrigerant, an electric motor for driving the compression portion, and a housing, which receives the compression portion and the electric motor. The motor-driven compressor further includes a drive circuit for driving the electric motor. The drive circuit is received in an accommodation space provided in the motor-driven compressor. The drive circuit includes a high voltage circuit for driving the motor and a low voltage circuit for control. In general, the low voltage circuit for control is connected to a communication lead, which is drawn from the inside to the outside of the accommodation space and connected to an external control device for controlling the motor-driven compressor.
The motor-driving high voltage circuit (a power switching element) may release electromagnetic noise to the surroundings in intensity large enough to affect other electric components. Such electromagnetic noise is easily propagated to electric components on the low voltage side. When the electromagnetic noise is propagated to a communication lead on the low voltage side, the electromagnetic noise may be further propagated to the external control device, which is connected to the communication lead. Reduction of the electromagnetic noise propagated to the communication lead is thus desired.